What is NAD and why is it important?
Nicotinamide Adenine Dinucleotide (NAD) is a coenzyme found in every cell of the human body. It is involved in hundreds of metabolic processes, acting as a vital molecule that allows enzymes to perform their functions effectively. Niacin, nicotinamide and tryptophan are precursors used to synthesise NAD(1).
At its core, NAD helps our cells turn nutrients from our food into usable energy. This energy, in the form of adenosine triphosphate (ATP), powers everything from muscle contraction to brain function and DNA repair. Without sufficient NAD, these processes can slow down, potentially affecting how energetic we feel(2).
NAD exists in two main forms:(2)
- NAD+ (oxidised form) – the active version that participates in energy metabolism.
- NADH (reduced form) – the form that carries electrons during the process of ATP generation.
The constant conversion between NAD+ and NADH is what keeps our cells functioning efficiently. As we age, however, NAD levels naturally decline, which may contribute to feelings of fatigue, slower metabolism, and some of the biological hallmarks of ageing(2).
Ongoing research continues to explore NAD’s wider influence on longevity, DNA repair, and metabolic health, making it a fascinating focus within nutritional and biomedical science.
How does NAD support Cellular Energy?
To understand NAD’s importance, it helps to picture the body’s cells as tiny power plants. Inside each cell are mitochondria, specialised structures that convert the carbohydrates, fats, and proteins in the food we eat into ATP, the energy currency our body uses to function.
NAD acts as a coenzyme in this process, helping key enzymes carry out redox (reduction-oxidation) reactions that release energy. In simple terms, NAD+ collects electrons from nutrients and transfers them through a series of reactions within the mitochondria. This electron transfer is essential for generating ATP(2).
Without adequate NAD, this energy-producing system becomes less efficient, which can result in decreased energy production and a possible feeling of tiredness or sluggishness on a cellular level.
As well as being central to energy metabolism, NAD is also an essential cofactor for enzymes such as sirtuins, and poly (ADP-ribose) polymerases. These enzymes play key roles in maintaining cellular health by regulating DNA repair, controlling inflammation, and supporting mitochondrial function. This connection between NAD and sirtuin activity has positioned NAD as a central molecule in discussions about healthy ageing and cellular health(2).
Understanding Vitamin B3 (Niacin) and NAD-Related Pathways
One of the nutrients involved in the body’s normal metabolic pathways including supporting synthesis of NAD, is vitamin B3, also known as niacin. This vitamin plays several well-established roles and contributes to:(3)
- normal energy-yielding metabolism
- reduction of tiredness and fatigue
- normal psychological function
- normal functioning of the nervous system
Niacin is an essential vitamin we get from food such as wholegrains, fish and meat. Once eaten, the body can use different forms of niacin to support its normal metabolic pathways, some of which eventually feed into how NAD is produced and recycled within cells.
One form of vitamin B3 (niacin) you may hear about is nicotinamide riboside (NR). NR is simply another way of providing niacin to the body. NR can be converted into forms that the body uses as part of its everyday cellular metabolism, including pathways that relate to NAD(4).
The most practical way for most people to support the body’s natural metabolic pathways, including those that involve NAD, is to maintain overall healthy habits.
Are there natural ways to support our NAD levels?
While NAD supplements are increasingly popular, it’s worth noting that lifestyle and diet play a significant role in maintaining healthy levels naturally. Here are several everyday steps to support NAD production through your daily habits:
1. Eat a Balanced, Nutrient-Dense Diet
NAD is synthesised from vitamin B3 (niacin) and related compounds, including nicotinamide and tryptophan. (5)Foods naturally rich in these nutrients can therefore help support the body’s ability to produce NAD.
Niacin-rich foods
Poultry (chicken, turkey)
Fish (tuna, salmon, sardines)
Beef and pork
Peanuts and peanut butter
Brown rice and whole grains
Mushrooms
Tryptophan-rich foods
Eggs
Dairy products (milk, cheese, yogurt)
Turkey and chicken
Soy products (tofu, tempeh)
Seeds (pumpkin, sesame, sunflower)
Nuts (almonds, cashews)
Other supportive foods
These don’t directly supply niacin or tryptophan but support overall metabolic processes that maintain healthy NAD levels:
Green leafy vegetables
Legumes
Avocado
Including a variety of these foods as part of a balanced diet ensures the body receives the nutrients it needs to maintain NAD production.
2. Engage in Regular Physical Activity
Exercise is one of the most effective natural ways to increase NAD levels. Physical activity stimulates mitochondrial biogenesis i.e. the creation of new mitochondria and enhances the activity of enzymes that rely on NAD. (6)Both aerobic and resistance training have been associated with improved NAD metabolism and energy efficiency(7).
3. Prioritise Quality Sleep
During sleep, the body undergoes vital processes that restore cellular energy and repair DNA. NAD plays a key role in these processes, serving as both an enzyme cofactor and a substrate involved in regulating the circadian rhythm. The sleep–wake cycle and circadian rhythms are disturbed by an age-associated decline in NAD levels. (8)Ensuring quality sleep may help to maintain healthy NAD-related pathways and overall energy balance.
4. Limit Alcohol Consumption
Alcohol metabolism consumes NAD, converting it into NADH and disrupting redox balance and impairing other NAD+-dependent functions. Excessive alcohol intake can therefore deplete NAD levels and affect normal energy production. Moderation, or abstaining altogether, supports the body’s ability to sustain adequate NAD(9).
Summary
NAD is an essential molecule that underpins energy metabolism, DNA repair, and overall cellular health. While our natural NAD levels tend to decline with age, lifestyle choices and balanced nutrition can help maintain them.
The most practical and reliable way to support the body’s natural metabolic processes is through a balanced lifestyle. Eating a varied diet that includes sources of niacin and other essential nutrients, staying physically active, getting enough sleep, and managing stress all contribute to supporting overall wellbeing.
For those who want more personalised advice on nutrition or specific health concerns, speaking with a registered dietitian or another qualified healthcare professional can help you make informed choices that suit your individual needs.
Learn more about our products here.
 |
This article was written by Caroline Hill who is a qualified dietitian with almost 20 years’ experience, having worked in the NHS and medical nutrition industry. She runs Caroline Hill Nutrition providing nutrition consultancy services to the food and medical nutrition industry, corporate wellness programmes and supporting 121 private clients. |
References:
1. Zapata-Pérez R, Wanders RJA, van Karnebeek CDM, Houtkooper RH. NAD+ homeostasis in human health and disease. EMBO Mol Med. 2021 Jul 7;13(7):e13943. doi: 10.15252/emmm.202113943. Epub 2021 May 27. PMID: 34041853; PMCID: PMC8261484.
2. Covarrubias AJ, Perrone R, Grozio A, Verdin E. NAD+ metabolism and its roles in cellular processes during ageing. Nat Rev Mol Cell Biol. 2021 Feb;22(2):119-141. doi: 10.1038/s41580-020-00313-x. Epub 2020 Dec 22. PMID: 33353981; PMCID: PMC7963035.
3. EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA); Scientific Opinion on the
substantiation of health claims related to niacin and reduction of tiredness and fatigue (ID 47), contribution to normal energy yielding metabolism (ID 51), contribution to normal psychological functions (ID 55), maintenance of normal blood flow (ID 211), and maintenance of normal skin and mucous membranes (ID 4700) pursuant to Article 13(1) of Regulation (EC) No 1924/2006. EFSA Journal 2010;8(10):1757 [17 pp.]. doi:10.2903/j.efsa.2010.1757.
4. Amjad S, Nisar S, Bhat AA, Shah AR, Frenneaux MP, Fakhro K, Haris M, Reddy R, Patay Z, Baur J, Bagga P. Role of NAD+ in regulating cellular and metabolic signaling pathways. Mol Metab. 2021 Jul;49:101195. doi: 10.1016/j.molmet.2021.101195. Epub 2021 Feb 17. PMID: 33609766; PMCID: PMC7973386.
5. Cantó C, Menzies KJ, Auwerx J. NAD(+) Metabolism and the Control of Energy Homeostasis: A Balancing Act between Mitochondria and the Nucleus. Cell Metab. 2015 Jul 7;22(1):31-53. doi: 10.1016/j.cmet.2015.05.023. Epub 2015 Jun 25. PMID: 26118927; PMCID: PMC4487780.
6. Sorriento D, Di Vaia E, Iaccarino G. Physical Exercise: A Novel Tool to Protect Mitochondrial Health. Front Physiol. 2021 Apr 27;12:660068. doi: 10.3389/fphys.2021.660068. PMID: 33986694; PMCID: PMC8110831.
7. Walzik D, Jonas W, Joisten N, et al. Tissue-specific effects of exercise as NAD+-boosting strategy: Current knowledge and future perspectives. Acta Physiol. 2023; 237:e13921. doi:10.1111/apha.13921
8. Weiss C. Vitamin B3 Ameliorates Sleep Duration and Quality in Clinical and Pre-Clinical Studies. Nutrients. 2025; 17(12):1982. https://doi.org/10.3390/nu17121982
9. Lee J, Lee JY, Kang H. Excessive alcohol consumption: a driver of metabolic dysfunction and inflammation. Front Toxicol. 2025 Sep 29;7:1670769. doi: 10.3389/ftox.2025.1670769. PMID: 41090150; PMCID: PMC12515849.